Cam burring apparatus



April 2, 1940. J. c. BAKER 196092,

CAM BURRING APPARATUS Filed April 19, 1938 2 Sheets-Sheet 1 -APl'il 2 1940 .1. c. BAKER 2,196,092

CAM BURRING APPARATUS Filed April 19, 1938 2 sheets-sheet 2 Fig@ 3 wow/kw ../'UH/v L'. BHKER Patented Apr. 2, 1940 UNITED STATES CAM BURRING APPARATUS John C. Baker, Worcester, Mass., assigner yto Norton Company, Worcester, Mass., a `corporation` of Massachusetts j Application April 19, 1938, Serial No. 202,926 s claims. (o1. 51'-5's) The invention relates to lapping machines, and

contemplates an apparatus to take olf the sharp j edges of any surfaces of revolution such as a camshaft bearing or a cam.

One object of the invention is to provide an apparatus for smoothing the edges of the cams of an automotive camshaft. Another object of the invention is to provide an attachment for a cam lapping machine whereby the individual cams 101 can be burred. Another object of the invention is to produce a camshaft or similar article the sharp corners of which are eliminated. Another object of the invention is to provide an apparatus whereby a camshaft or similar article may be 5.1 simultaneously lapped and burredgthus achieving the burring of the camshaft without any substantial additional expense. Other objects will be in part obvious orin part pointed out hereinafter.

U The invention accordingly consists in the feachanical features of this invention:

Figure l is a vertical sectional view of a portiony of a camshaft lappingv machine together with the cam burring apparatus of theinvention;

`Figure 2 isvafragmentary side elevation of one of the cam burring heads;

Figure 3 is an enlarged sectional View taken on the line 3-3 of Figure 1;

Figure 4 is a plan view of the cam burring attachment on an enlarged scale;

Figure 5 is an elevation of thev controlling lever and associated parts of the cam burring attachment, the view being taken looking toward the front of the machine;

Figure 6 is a fragmentary plan view of one end of a camshaft lapping machine showing -a modified form of cam burring attachment mounted thereon;

Figure rI is a sectional view taken'on the line 1-1 of Figure 6;

Figure 8 is a sectional view on an enlarged scale taken along `the line 8-8 of Figure 7;

Figure 9 is a fragmentary sectional View taken along the line 9 9 of Figure 6;

Figure 10 is a fragmentary view on an enlarged scale of one of the cam burring heads;

two of many possible embodimentsvof theme- "Figure 11l is adevelopment of cam slots of a sleeve shown in Figure 8.

As conducive to a clearer lunderstanding of the present invention, it is noted that patent to Herbert S. Indge and George E. Hulbert, No. 2,092,734

describes and claims a camshaft lapping machine for lapping the cams of an automobile camshafu and also the bearings thereof. In such a machine the lapping is achieved' with sandpaper; The cams and thebearings of the vcamshaft have been previously ground and as a result of the grinding and lapping operationsv 'the edges of the various cams and also some' times of the bearing portions are very sharp. In some automobile factories the sides of the cams are not turned or ground but have the Surfaces originally` imparted to them by the forging proc` ess. The sharp .edges of such camshafts, after the grinding and lapping' operations, are also jagged. In these and also in the other cases the workmens hands are frequently cut bythe sharp edges of the cams.

In shop terminology, when a ysharp corner is smoothed off, it is said to be burred A sharp jagged corner is also sometimes referred to as a burn The present invention provides burring apparatus by which is meant apparatus toremove or smooth the sharp edges of ya work piece. The priorpatent to Indge and Hulbert referred to includes a table supporting the workpiece which is given a reciprocatory motion. Upon this table I may mount the cam burring apparatus in the form of an attachment. Thus I am enabled to perform the burring operation While the lap-ping operation is proceeding, thereby avoiding any substantial additional expense for the burring of the camshafts.

Referring first to Figure 1,.the machine of the aforesaid patent includes a table mounted for reciprocation in the direction of the axis of the camshaft 2| to be lapped. The machine also includesl a bar 22 (and another one, ,not

shown) supporting reciprocating slides 23., The slides 23 (only one of which is shown) have dovetailed portions 24 constituting ways Asupporting lapping arms 25, having complementary' waystting the ways 2,4. By means of a gib 21 and screw 28 the several lapping arms 25 can be fastened in adjusted position opposite the cams 3l of a camshaft 2|. This adjustment along the length ofthe camshaft is provided so that the ,machine may handle different styles of camshafts.

Each lapping arm has a long aperture 32 in which is located a slide `33. By means of a the frame members B5 is a shaft T5.

spring 34 attached at its front end to a pin 35 extending between the sides of thearm 25 in the aperture 32, the slide 33 is urged in the direction of the cam 3|'. A master camshaft having a plurality of master cams of the same size and angular position as the cams on the product camshaft 2l is provided to cause each slide 33 to reciprocate as the camshaft 2l revolves. This master camshaft is not shown herein and the patent to Indge and Hulbert may be referred to. Anti-friction rollers 3! and 38 are provided, the rollers 3'! being mounted in an adjustable bar 39 adjusted vertically by means of a screw 40.

Each slide 33 is provided `with a nose member 42 which carries a yieldably mounted support 43 which serves as a support for the abrasive paper when in contact with the work. A roll of abrasive paper, not shown, delivers a strip 44 of abrasive paper or cloth to the yieldable member 43 of the nose strip is wound up on a spool 45 carried by a stud 46 which is supported by a bracket 4'! carried by the arm 25. One side 48 of the spool 45 constitutes a ratchet wheel and a pawl 5D is provided to prevent retrograde movement of the spool 45. The operator can Wind up a given amount of the strip 44 at any time when the operating section thereof has been worn out.

In order to prevent sidewise slipping of the paper 44 on the nose 42, side guide plates 5I fastened to the sides of the nose 42 are provided. In order to prevent slipping of the abrasive paper 44 in a vertical direction, a strip of fairly coarse flexible abrasive cloth 52 extends around the end of the nosepiece 42 and is clamped in place thereon by means of clamping members 53 andr 54. The yieldably mounted nose piece 42 is held in a forward position by means of a spring 55, allowing a yielding engagement of the abrasive paper with the periphery' of the cam being lapped.

Referring now to Figure 4, the machine includes a work driving member 60 which is rotatably mounted on the table and which is rotated by a mechanism described in the aforesaid patent. The machine also includes a tail center Si supported by the table 2D.

The foregoing is descriptive of the machine of the aforesaid Patent No. 2,092,734 and i-ncludes apparatus cooperating with the present invention. Preferably all the instrumentalities described in the aforesaid patent will be used. The apparatus which is more particularly the subject of the present invention may conveniently be mounted upon the table 2U- and will' now be described.

Referring now to Figures l and 4, I provide three frame members near each end of the table 23 and in the middle thereof. Frame members 55 include ways 66 at the front thereof, a flat surface 6'! at the rear thereof, and a gib 38 which may be tightened by means of a bolt 69. The ways E6' fit a portion 1E! of the table 2B and the ways 6'! and gib 68 t a portion 'H of the table 2?. Thereby the frame members 55 may be adjustably fastened to the top of the table 2G, the cross sections all along the table 2? being similar. Extending between and journalled in Fastened to this shaft 'l5 is a bell crank operating lever 3'6. This lever i6 has an arm 'lla the outer end of which supports a shaft '18; Coaxial with the shaft 'E8 is a similar shaft 18a. At least one arm 7'! is keyed to the shaft 'l5 and also supports the shaft 18. A pair of arms 'll support the shaft 18a. Shafts 18 and 18a are always at the same level and move upwardly and dov/nwardly in response to manual actuation of the bell crank lever` T6.

The shafts 'I8 and 18a support a plurality of bell crank brackets 19. Each bell crank bracket 'i9 has a square opening 80 receiving a slide 8! in which is located an eccentric 32 on a shaft B3. The shaft 83 is journalled in the frame member G5. Referring now to Figure 4, at the right-hand end of the shaft 83 is fastened a spur gear 84 which meshes with a pinion. gear 35 on the end of an armature shaft 8G of a motor 8l. rl'he motor may be mounted upon the tailstock 8 of the machine. Thus the shaft S3 is ren volved and the several eccentrics 82 are rotated. As eccentrics 82 are located in the sliding blocks 85, the bell crank brackets T9 are oscillated about stationary pivots constituting the shafts 13 and 78o.. The shafts 18 and 18a are shown in Figure at the upper position thereof, in which position the brackets 'I9 hold abrasive stones 98 in contact with the several cams 3l. By moving the bell crank hand lever 76 in a counterclock- Awise direction, the stones are moved away from the cams 3i.

Considering now the manner in which the bell crank brackets 19 support the stones 93, and referring to Figures 1, 3 and 4, each bell crank bracket 'i9 has forked ends 9! supporting plates si. The stones 90 may be made of any suitable abrasive suitably bonded, for example of crystalline alumina or silicon carbide abrasive grain bonded with vitried bond or resinoid bond. On the other` hand, they may be natural abrasive stones. They are rectangular parallelopipeds in shape and at the ends they are cemented to holding plates 94. The holding plates 94 are pivoted at 95 to the supporting plates 92 and springs G6 connect the ends of the plates B4 opposite' the pivots 95. Considering now Figure 3, it will be seen that the stones 90 are held at an angle to the sides of the cam 3| and', furthermore, they are resiliently pulled together. As the nose of the cam reaches the stones 90, they can separate to allow it to move between them. The stones 90 abrade the edges of the cam and so aresaid to burr the. cam.

Referring now to Figures 2 and 4, there are provided additionally arms 9'! integral with certain brackets 'I9 which. support narrow stones 98 spring pressed by a spring 99 against cam bearings l'li. These cam bearings 100 are cylindrical portions and have oil grooves l0! the sides of which are burred by the stones 9B.

The various parts mentioned will remain in the lower or inoperativeV position when' moved thereto simply by the force of gravity assisted. if desired, by means of a spring |05 extending between frame member 65 and an arm 508 extending rearwardly from the bell crank lever 1G. A screw 29'! provides' means for accurately locating the Lipper position of the parts and a detent H38 cooperates with a latch |09 pivoted between ears H6 extending rearwardly from the bell crank levers 'I3 to hold the lever 16 in the position shown. A hand grip lever l l2 pivoted at l I3 to the lever 16 is connected by a chain H4 to an arm H5 extending rearwardly from the latch i539, thereby to release the lever T6. A spring HG causes the latch automatically to engage.

The operator places the camshaft to be lapped and burred between the tail center Sl and the work driving member 60 while. the bell crank lever 16 is in forward or unlatched position. He

then moves the bell crank lever 16 rearwardly which raises the stones 90 and vlill-against the cams and the grooves in the bearings. At any timethe operator may do the other things to prepare the machine forloperation, as set forth in the aforesaid patent to Indge and Hulbert and then he may apply the power causing the shaft 2| to rotate, thetable 20 to reciprocate, and the slides 23 and 33 to reciprocate, as set forth in the aforesaid patent. At the same time, he energizes the motor 8| which causes the stones 99 and 98 to be oscillated. The rotation of the camshaft and the oscillation of the stones produces a very effective burring vaction to remove the sharp corners from the several cams and also from the sides of the grooves in the bearing portions. The entire burring apparatus is carried by the table which in turn carries the camshaft and is, therefore, unaffected by the various reciprocating motions of the machine.

Figures 6 to 11 inclusive illustrate a modification of the invention which will now be described. As in the aforesaid patent, a sprocket |20 is mounted on the spindlel |2| of the work driving member 60. A sprocket chain, not shown, extends from this sprocket |20 to another sprocket eventually to drive the master camshaft, not shown. According to the present invention I mount an additional sprocket |22 to be driven by the chain. This sprocket |22 is on the end of a shaft |23 journalled in a frame member |24 which, as shown in Figure '1, is fastened to the table 20. This frame member |24 has ways |25, a fiat portion |26 at the rear thereof, and a gib |21 which may be tightened by means of a bolt |28. The ways |25 t on the portion 10 of the table and the ways |26 and gib |21 t the portion 1| of the table, so that the frame member |24, and additional frame members substantially like it which are not shown, may be adjustably fastened to the top of the table 20.

The shaft |23 has fastened thereto a plurality of cams 30. Each cam |30 is housed in a box |3| which is lsupported by the shaft |23. Referring to Figures 7 and 8, extending radially outwardly from the box |3| is a sleeve |32 which may be integral with the box |3|. 'I'his sleeve |32 has inclined slots |33 which are shown in the developed view of Figure 11. A tubular supporting member |34 has holes |35 on opposite sides thereof and a pin |36 extends through the holes and the slots |33 into the head |31 of a tappet rod |38, the lower end of which bears against one of the cams |30. There are as many of these mechanisms as there are cams on the product camshaft to be lapped.

The upper end of the sleeve |32 is blocked by a screw plug |39. In the sleeve |32 and between the plug |39 and the head |31 is a spring |40. This spring |40 holds the tappet rod |38 against the cam |30 and, therefore, the pin |36 rides up and down, following the shape of the cam |30. As it does so, however, it twists first in one direction and then in the other on account of the angularity of the slots |33. The tubular supporting member |34 must move up and down and also must oscillate with the pin |36.

The tubular supporting member |34 has an offset arm portion |4| which supports a stone holding device clearly shown in Figures 7 and 10. As therein shown, a stud |42 is attached to the top of the offset arm |4| and supports a pair of arms |43 and |44 one of which has a hub portion at the lower part of the stud 42 and the other of which has a hub portion at the upper part of the stud |42. `A` spring |45 tends to separate the front portions of the arms |43 and 44, thereby urging together the upper and rearward ends of said arms. Springs |41 coiled around pins |48 and ears |49 and |50 serve to hold stones I5| to the arms |43 and |44. A central pin |52 projecting upwardly from the offset portion |4| prevents the stones |5| from approaching each other more than the desired amount when the stones |5| are not in contact.

with a cam 3|.

The axis of oscillation of the sleeve |34 extends almost tangentv to the cylindrical portion of the cam 3| At all events, a somewhat irregular reciprocating and oscillating motion is imparted to the stones |5| which effectively burr the sides of the cams 3|. The oscillating motion produces a rounding over of the edges of the cams 3| and the reciprocating motion, by causing periodically a greater relative motion between the cam and the stone, increases theY cutting action of the stones |46.

Extending forwardly from each box |3| is a short arm |55 through which extends a bolt |56 secured to a bar |51 supported by the frame members |24. Around each bolt |56 is a spring |58. These springs hold the stones |46 against the several cams 3| and also permit the entire mechanism to swing in a counterclockwise direction when the noses of the cams 3| engage the stones.

At any time the operator may remove all the stones 46 from cams'3l by turning a hand crank |60, Figure 6. As shown in Figures 6 and '1, the hand vcrank |60 is fastened to a long shaft |6| which extends the length ofv the table 20. Referring now to Figure 7, fastened to the shaft |6| at each end of the table 20 is a cam |62 (only one being shown) which engages a lever |63 pivoted on a stud |64 projecting from the frame member |24. The other end of the lever |63 carries an angle iron |65 which extends the length of the table 20. Thus there is one long shaft 6| across the machine and one long angle bar |65 across the machine and a cam |62, lever |63 and stud |64 at each end of the machine. Turning of the hand crank |60 moves the angle iron |65 downwardly. All of the short arms |55 are in position to be engaged by the angle iron |65. Accordingly, by operating the hand crank |60, the operator may move all the burring devices away from the camshaft 2|, and the shape of the cam |62 is such that they can readily be held in this lowered position.

Referring now to Figure 9, there is therein illustrated an alternative device for b-urring the groove |0| in a cam bearing |00. Keyed to the shaft |23 is a cam |10. This cam |10 is located in a housing |1| which has integrally secured thereto a forked arm |12 supporting a burring arm |13 by means of a pin |14. A tappet rod |15 extends between the cam |10 and the burring arm |13 through the arm |12. A stone |16 which preferably has a tapered end is located in the groove |0|. This stone is cemented to a holder |11 which is held by split portion |18 of the burring arm 13. A spring |19 extends between a portion |80 of the arm |13 and the forked arm |12. This spring causes the retrograde motion to force the tappet |15 against the cam |10. A spring |8| extends between the bar |51 and the arm |12, thus holding the stone |16 against the cam groove |0| and also allowing the arm |12 to be depressed by means of the angle iron IE5 which engages the boss |82 on the arm |12.

It will thus be seen that there has been provided by this invention apparatus in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. Apparatus of the class described comprising means rotatably to hold a camshaft or the like, means to hold abrasive stones against corners of the cams thereof including means urging said abrasive stones towards each other, and means angularly to oscillate said stones in contact with the cams.

2. In apparatus of the class described, means rotatably to hold a camshaft or the like, an abrasive stone, means to oscillate said abrasive stone about an axis substantially tangent to a work piece element on said camshaft, and means to reciprocate said abrasive stone in a direction parallel to the axis of oscillation.

3. In apparatus of the class described, a table, a reciprocating polisher adjacent said table comprising an abrasive element and means to reciprocate it, and a cam burring attachment mounted on said table comprising a holder for abrasive stones, means to oscillate said holder, and means to raise and lower said holder.

4. In apparatus of the class described, a table, a sandpaper polishing head adjacent said table,

anda. cam burring attachment on said table comprising a holder for abrasive stones, and means to reciprocate said holder.

5. A cam burring attachment comprising a pair of abrasive stones, a holder for said stones holding them so that a pair of surfaces thereof made a dihedral angle, spring means urging said stones towards each other to change the dihedral angle, means to oscillate the holder, and means to raise and lower the holder including means to maintain the holder in raised or operative position.

6. In apparatus of the class described, a frame, means to clamp the frame to a table, a shaft supported by the frame, a hand lever to operate the shaft, arms extending from the shaft, a second shaft supported by the arms, bell crank levers supported by the second shaft, means to oscillate the bell crank levers, and abrasive stones carried by the bell crank levers.

7. In apparatus of the class described, a main shaft, cams mounted on said main shaft, boxes around said cams, tappets against said cams supported from said boxes, a sleeve around said tappets, connections between the tappets and the sleeves to cause the sleeves to be reciprocated by the tappets, inclined plane means to cause the sleeves also to be oscillated by the tappets, an offset arm on the sleeve, and abrasive stones carried by the offset arm.

8. In apparatus as claimed in claim '7, the combination with the parts and features therein specified, of means to raise and lower the boxes to hold the stones away from a camshaft or cause them to engage it.

JOHN C. BAKER. 

